4-12 4. Geographic Shapefile Concepts Overview The following sections describe the geographic entity type displayed in each shapefile, as well as the record layout for each file, in alphabetical order. A listing of all available shapefiles, including vintage and geographic level (state, county and national), precedes the description of the entity type. Shapefiles do not exist for geographic layers where there is no data in the MTDB (e.g., states that have no American Indian/Alaska Native/Native Hawaiian Areas will not have an AIANNH shapefile). 4.1 American Indian / Alaska Native / Native Hawaiian (AIANNH) Areas 4.1.1 Alaska Native Regional Corporations (ANRCs) Alaska Native Regional Corporations geography and attributes are available in the following shapefile: Alaska Native Regional Corporation (ANRC) State Shapefile (Current) ANRCs are corporations created according to the Alaska Native Claims Settlement Act (Pub. L. 92–203, 85 Stat. 688 (1971); 43 U.S.C. 1602 et seq. (2000)). The laws of Alaska organize Regional Corporations to conduct both the for-profit and non-profit affairs of Alaska Natives within defined regions of the state. The Census Bureau treats ANRCs as legal geographic entities. Twelve ANRCs cover Alaska except for the area within the Annette Island Reserve (an AIR under the governmental authority of the Metlakatla Indian Community). The Census Bureau offers representatives of the twelve ANRCs the opportunity to review and update the ANRC boundaries. TIGER/Line Shapefiles represent ANRCs with a 5-character FIPS code unique within Alaska and a nationally unique 8-character ANSI code. See Appendix F-1 for ANRC record layout. 4.1.2 American Indian/Alaska Native/Native Hawaiian (AIANNH) Areas American Indian, Alaska Native and Native Hawaiian area geography and attributes are available in the following shapefile: American Indian/Alaska Native/Native Hawaiian (AIANNH) Area National Shapefile (Current) This shapefile contains both legal and statistical AIANNH entities for which the Census Bureau publishes data. The legal entities consist of federally recognized AIR and ORTL areas, state-recognized AIRs and Hawaiian Home Lands (HHLs). American Indian Tribal Subdivisions (AITS) and Alaska Native Regional Corporations (ANRCs) are additional types of legal entities, displayed in separate shapefiles discussed in this chapter. The statistical entities displayed in these shapefiles are Alaska Native Village Statistical Areas (ANVSAs), Oklahoma Tribal Statistical Areas (OTSAs), Tribal Designated Statistical Areas (TDSAs), and State Designated Tribal Statistical Areas (SDTSAs). The AIANNH shapefiles contain a unique polygon record for each AIR or ORTL, HHL, ANVSA, and American Indian statistical geographic entity. For example, the Fort Peck Indian Reservation will have two records: one for the reservation portion and another for the Off-Reservation Trust Land portion. Entities with only a single component (e.g., HHL, ANVSA, American Indian statistical geographic entity, reservation without any associated ORTL, or an entity that is only ORTL), will contain a single record.
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4. Geographic Shapefile Concepts Overview The following sections describe the geographic entity type displayed in each shapefile, as well as the
record layout for each file, in alphabetical order. A listing of all available shapefiles, including vintage and
geographic level (state, county and national), precedes the description of the entity type. Shapefiles do
not exist for geographic layers where there is no data in the MTDB (e.g., states that have no American
Indian/Alaska Native/Native Hawaiian Areas will not have an AIANNH shapefile).
4.1 American Indian / Alaska Native / Native Hawaiian (AIANNH) Areas
4.1.1 Alaska Native Regional Corporations (ANRCs) Alaska Native Regional Corporations geography and attributes are available in the following shapefile:
Alaska Native Regional Corporation (ANRC) State Shapefile (Current)
ANRCs are corporations created according to the Alaska Native Claims Settlement Act (Pub. L. 92–203,
85 Stat. 688 (1971); 43 U.S.C. 1602 et seq. (2000)). The laws of Alaska organize Regional Corporations
to conduct both the for-profit and non-profit affairs of Alaska Natives within defined regions of the state.
The Census Bureau treats ANRCs as legal geographic entities. Twelve ANRCs cover Alaska except for
the area within the Annette Island Reserve (an AIR under the governmental authority of the Metlakatla
Indian Community). The Census Bureau offers representatives of the twelve ANRCs the opportunity to
review and update the ANRC boundaries.
TIGER/Line Shapefiles represent ANRCs with a 5-character FIPS code unique within Alaska and a
nationally unique 8-character ANSI code.
See Appendix F-1 for ANRC record layout.
4.1.2 American Indian/Alaska Native/Native Hawaiian (AIANNH) Areas
American Indian, Alaska Native and Native Hawaiian area geography and attributes are available in the
following shapefile:
American Indian/Alaska Native/Native Hawaiian (AIANNH) Area National Shapefile (Current)
This shapefile contains both legal and statistical AIANNH entities for which the Census Bureau publishes
data. The legal entities consist of federally recognized AIR and ORTL areas, state-recognized AIRs and
Hawaiian Home Lands (HHLs). American Indian Tribal Subdivisions (AITS) and Alaska Native Regional
Corporations (ANRCs) are additional types of legal entities, displayed in separate shapefiles discussed in
this chapter. The statistical entities displayed in these shapefiles are Alaska Native Village Statistical
Areas (ANVSAs), Oklahoma Tribal Statistical Areas (OTSAs), Tribal Designated Statistical Areas
(TDSAs), and State Designated Tribal Statistical Areas (SDTSAs).
The AIANNH shapefiles contain a unique polygon record for each AIR or ORTL, HHL, ANVSA, and
American Indian statistical geographic entity.
For example, the Fort Peck Indian Reservation will have two records: one for the reservation portion and
another for the Off-Reservation Trust Land portion.
Entities with only a single component (e.g., HHL, ANVSA, American Indian statistical geographic entity,
reservation without any associated ORTL, or an entity that is only ORTL), will contain a single record.
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AIANNH areas cannot overlap another tribal entity. Tribal subdivisions are the exception, which subdivide
some American Indian entities and ANVSAs that exist within ANRCs. In cases where more than one tribe
claims jurisdiction over an area, the Census Bureau creates a joint-use area as a separate entity to define
this area of dual claims.
See Appendix F-2 for AIANNH record layout.
4.1.2.1 Legal Entity Definitions American Indian Reservations—Federal (federal AIRs)
Federal AIRs are areas set aside by the United States for the use of federally recognized tribes. The
exterior boundaries of federal AIRs are in tribal treaties, agreements, executive orders, federal statutes,
secretarial orders and/or judicial determinations. The Census Bureau recognizes federal reservations as
territory over which American Indian tribes have governmental authority (e.g., colonies, communities,
Indian colonies, Indian communities, Indian Rancherias, Indian Reservations, Indian villages, pueblos,
rancherias, ranches, reservations, reserves, settlements, villages, or other descriptions). The Bureau of
Indian Affairs (BIA) within the U.S. Department of Interior regularly publishes a list of federally recognized
tribal governments in the Federal Register. The Census Bureau contacts representatives of these
federally recognized American Indian tribal governments to identify the boundaries for federal
reservations. Federal reservations may cross state, county, county subdivision, and/or place boundaries.
Contact information for federally recognized tribes; please visit the Bureau of Indian Affairs website at
<https://www.bia.gov/>
< https://www.usa.gov/tribes>
Census Bureau assigns each federal AIR and reservation equivalent joint-use area with a nationally
unique 4-character census code (0001 to 4999). These census codes are in alphabetical order of AIR
names nationwide, except that joint-use areas appear at the end of the code range (4900 to 4999).
Federal AIRs and reservation equivalent joint-use areas also have a nationally unique 8-character GNIS
code.
American Indian Reservations—State (state AIRs)
Some state governments establish state AIRs for tribes recognized by the state. A governor-appointed
state liaison provides the names and boundaries for state-recognized AIRs to the Census Bureau. State
reservations may cross county, county subdivision and/or place boundaries.
Census Bureau assigns each state AIR with a nationally unique 4-character census code (9000 to 9499)
and a nationally unique 8-character GNIS code.
American Indian Trust Lands
American Indian Trust Lands are areas for which the United States holds title in trust for the benefit of a
tribe (tribal trust land) or for an individual American Indian tribal member (individual trust land or
allotment). Trust lands may be located on (on-reservation) or off an AIR (off-reservation). The Census
Bureau recognizes and tabulates data for reservations and ORTLs because American Indian tribes have
governmental authority over these lands. Tribal governmental authority generally applies to lands located
off the reservation only when the lands are in trust status. In Census Bureau data tabulations, ORTLs are
always associated with a specific federally recognized reservation and/or tribal government. A tribal
government appointed liaison provides the name and boundaries of their ORTLs. The Census Bureau
The Census Bureau recognizes MCDs in 29 states, Puerto Rico, and the Island areas. The District of
Columbia has no primary divisions, and the Census Bureau treats the incorporated place of Washington
as an MCD equivalent for statistical purposes. In 23 states, all or some incorporated places are not part of
any MCD. These places also serve as primary legal county subdivisions and have a FIPS MCD code that
is the same as the FIPS place code. The GNIS codes also match for those entities. In other states,
incorporated places are part of the MCDs where located or the pattern is mixed—some incorporated
places are independent of MCDs and others are included within one or more MCDs. The MCDs in 12
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states (see Figure 17) also serve as general-purpose local governments that generally can perform the
same governmental functions as Incorporated Places. The Census Bureau presents data for these MCDs
in all products that contain place data.
Connecticut Maine Massachusetts Michigan Minnesota New Hampshire New Jersey New York Pennsylvania Rhode Island Vermont Wisconsin
Figure 17: MCD States
In Maine and New York, AIRs exist outside the jurisdiction of any town (MCD) and thus serve as the
equivalent of MCDs for purposes of data presentation.
Statistical Entity Definitions
Census County Divisions (CCDs)
CCDs are areas delineated by the Census Bureau in cooperation with state and local officials for
statistical purposes (non-governmental units and have no legal functions). CCD boundaries usually follow
visible features and, in most cases, coincide with census tract boundaries. The Census Bureau gives
each CCD a name based on a place, county, or well-known local name to identify its location. CCDs exist
where:
• There are no legally established MCDs
• The legally established MCDs do not have governmental or administrative purposes
• The boundaries of the MCDs change frequently
• The MCDs are not generally known to the public
The Census Bureau has established CCDs for the following 20 states:
Alabama Arizona California Colorado Delaware Florida Georgia Hawaii Idaho Kentucky Montana Nevada New Mexico Oklahoma Oregon South Carolina Texas Utah Washington Wyoming
Figure 18: Census County Divisions
Census Subareas
Census subareas are statistical subdivisions of boroughs, city and boroughs, municipalities, and census
areas. Census areas are the statistical equivalent entities for counties in Alaska. Alaska and the Census
Bureau cooperatively delineate the census subareas to serve as the statistical equivalents of MCDs.
Unorganized Territories (UTs)
UTs defined by the Census Bureau in nine MCD states and in American Samoa, where portions of
counties or equivalent entities are not included in any legally established MCD or incorporated place. The
Census Bureau recognizes such separate pieces of territory as one or more separate county subdivisions
for census purposes. Each UT is given a descriptive name, followed by the designation “unorganized
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territory” and county subdivision FIPS and GNIS codes. The Census Bureau recognizes UTs in the
following states and equivalent areas:
Arkansas Indiana Iowa Maine Minnesota New York North Carolina North Dakota South Dakota
Figure 19: Unorganized Territories
Undefined County Subdivisions
In water bodies, primarily Great Lakes waters and territorial sea, legal county subdivisions do not extend
to cover the entire county. For these areas, the Census Bureau created a county subdivision with a FIPS
code of 00000 and GNIS code of 00000000 named “county subdivision not defined.” The following states
and equivalent areas have these county subdivisions:
Connecticut Illinois Indiana Maine Massachusetts Michigan Minnesota New Hampshire New Jersey New York Ohio Pennsylvania Rhode Island Wisconsin Puerto Rico
Figure 20: Undefined County Subdivisions
New England City and Town Area (NECTA) Codes
The county subdivision shapefiles also contain fields with codes for combined New England city and town
area, New England city and town area, and New England city and town area division. The NECTAs
consist of county subdivisions in New England only and users can merge county subdivision records to
form these areas without acquiring the individual NECTA shapefiles.
See Appendix I-3 County Subdivision State-based Record Layout.
4.9 Estates (United States Virgin Islands) Estate features and attributes are available in the United States Virgin Islands in the following shapefile:
Estate State-based Shapefile (Current)
Estates are subdivisions of the three major islands in the United States Virgin Islands (USVI). The estates
have legally defined boundaries and are generally smaller in area than the Census Subdistricts (county
subdivisions), but do not necessarily nest within these districts. The boundaries of the estates are
primarily those of the former agricultural plantations that existed at the time Denmark transferred the
islands to the United States in 1917. The names and boundaries of the estates are in common usage by
residents and in government administration. Estate boundaries have been substantially revised for the
2020 Census at the request of the USVI Office of the Lieutenant Governor, effective as of January 1,
2020. The 2010 and 2011 TIGER/Line products contain estate data in the Subminor Civil Division
(submcd) shapefiles.
See Appendix I-4 Estate (U.S. Virgin Islands Only) Record Layout.
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4.10 Hydrography (Area and Linear) Hydrography features and attributes are available in the following shapefiles:
Area Hydrography County-based Shapefile
Linear Hydrography County-based Shapefile
The area hydrography shapefile contains the geometry and attributes of both perennial and intermittent
area hydrography features (e.g., ponds, lakes, oceans, swamps, glaciers, and the area covered by large
streams represented as double-line drainage). Single-line drainage water features exist in the all lines
shapefile and the linear hydrography shapefile.
The linear hydrography shapefile contains all linear features with Hydrography (“H”) type MTFCCs in the
MTDB by county. The Census Bureau provides these shapefiles at a county geographic extent and in
linear elemental feature geometry. The linear hydrography shapefile includes streams/rivers, braided
streams, canals, ditches, artificial paths, and aqueducts. A linear hydrography feature may include edges
with both perennial and intermittent persistence.
Single-line drainage water features include artificial path features that run through double-line drainage
features (e.g., rivers and streams) and serve as a linear representation of these features. The artificial
path features may correspond to those in the USGS National Hydrographic Dataset (NHD). However, in
many cases the features do not match NHD equivalent feature and will not carry the NHD metadata
codes.
Shorelines for Area Hydrography exist in the all lines shapefiles and have MTFCCs of either “P0002”
(shoreline of perennial water feature) or “P0003” (shoreline of intermittent water feature).
See Appendix J-1 for Area Hydrography County-based Record Layout.
See Appendix J-2 for Linear Hydrography County-based Record Layout.
4.11 Landmarks (Area and Point) Landmark features and attributes are available in the following shapefiles:
Area Landmark State-based Shapefile
Point Landmark State-based Shapefile
The Census Bureau includes landmarks in the MTDB to locate special features and help enumerators
during field operations. Some of the more common landmark types include area landmarks (e.g., airports,
cemeteries, parks, and educational facilities) and point landmarks (e.g., schools and churches).
The Census Bureau adds landmark features to the database on an as-needed basis (and does not
attempt to ensure that all instances of a feature were included). The landmarks were not used to build or
maintain the 2010 Census address list and the absence of a landmark (e.g., hospital or prison) does not
mean that associated living quarters were excluded from the 2020 Census enumeration.
Area landmark and area water features can overlap. For example, a park or other special land-use
feature may include a lake or pond. In this case, the polygon covered by the lake or pond belongs to a
water feature and a park landmark feature. Other kinds of landmarks can overlap as well. Area landmarks
can contain point landmarks, but TIGER/Line Shapefiles do not contain links to these features.
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All landmarks have a MTFCC that identifies the type of feature and may or may not have a specific
feature name. A full MTFCC list with definitions for the 2021 TIGER/Line Shapefiles is in Appendix E.
Each landmark has a unique area landmark identifier (AREAID) or point landmark identifier (POINTID)
value.
See Appendix K-1 for Area Landmark State-based Record Layout.
See Appendix K-2 for Point Landmark State-based Record Layout.
4.12 Linear Features Linear elemental features are the spatial representation of 1-dimensional roads, hydrography, railroads,
and other miscellaneous features in the MTDB. A linear elemental feature can span one edge or multiple
connecting edges that share a common name and feature classification (MTFCC).
More than one linear elemental feature can share the same edge or group of connected edges. For
example, an edge may be associated with a linear feature called Oak Street. This same edge may be one
of several edges also associated with another linear feature called State Highway 57. The edge in
question has two names: Oak Street and State Highway 57. The Census Bureau designates one of these
names as primary and the others as alternates; usually the common street name (Oak Street) will be
primary.
The MTDB breaks/ends linear elemental features when the feature name changes. All spelling
differences result in a new feature. Features will also break at county boundaries, changes in
primary/alternate designation, MTFCC, and gaps in the geometry.
4.12.1 All Lines Each all lines shapefile describes the universe of edges that bound or are included within a county or
equivalent entity. The shapefile describes the geometry of each edge along with descriptive attributes and
unique identification numbers. These identification numbers provide the means for linking the edges to
alternate features (e.g. their names, address ranges, and adjacent faces).
The all lines features, and attributes are in the following shapefile:
All Lines County-based Shapefile
The all lines shapefile contains visible linear feature edges (e.g., roads, railroads, and hydrography), as
well as non-feature edges and non-visible boundaries. Additional attribute data associated with the edges
are available in relationship files that users must download separately.
The all lines shapefile contains the geometry and attributes of each topological primitive edge. Each edge
has a unique Topological Line Identifier (TLID). An edge’s left and right faces are identified by the
Topological Faces Identifier on the left side of the edge (TFIDL) and the Topological Faces Identifier on
the right side of the edge (TFIDR) attributes, which link to the TFID attribute in the Topological Faces
shapefile.
The left and right side of an edge is determined by the order of the points that form the edge. An edge is
oriented from the start node to the end node. If a person stands on an edge at the start node and faces
the end node, data listed in the fields carrying a right qualifier to the right of the edge. Users can employ
GIS software to plot the edges as directional vectors with arrows showing the orientation of edges.
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In the MTDB, edges may represent several types of features. The series of feature indicator flags
(Hydrography [HYDROFLG], Road [ROADFLG], Rail [RAILFLG] and Other Linear [OLFFLG]) indicate the
classes of features that share the edge. For example, a road may have embedded railroad tracks; the
corresponding edge will have both the ROADFLG and RAILFLG set. Generally, certain feature types
appear together on the same edge:
Feature Type Description
Road and Rail Roads with adjacent tracks, tracks embedded in roadways or tracks located in the median
Rail and Other Linear Feature Rail features located on dams and levees
Road and Other Linear Feature Road features located on dams and levees
Figure 21: Feature Types
The MTFCC identifies the specific code for the primary feature on the edge. For edges that represent
roads in combination with other features, the MTFCC in the all lines shapefile will reflect the road feature.
See Appendix L-1 for All Lines County-based Record Layout.
4.12.2 Coastline The coastline boundary is available in the following shapefile:
Coastline National Shapefile
The coastline shapefile includes all features within the MTDB class "Coastline," distinguished by the
MTFCC of L4150. The coastline shapefile uses the MTDB based on water measurement class for display
of statistical information only. The name assigned to each coastline feature is a short form of the name of
the large body of water bordered by this coastline feature.
See Appendix L-2 for Coastline National Record Layout.
4.12.3 Roads – Primary, Secondary and All Roads Linear road features and attributes are available in the following shapefiles:
Primary Roads National Shapefile
Primary and Secondary Roads State-based Shapefile
All Roads County-based Shapefile
Primary roads are generally divided limited-access highways within the Federal interstate highway system
or under state management. Interchanges and ramps distinguish these roads, and some are toll
highways. The primary roads shapefile contains all linear street features with a MTFCC of primary roads
(S1100) in the MTDB.
The primary and secondary roads shapefile contains all linear street features with MTFCCs of primary
roads (S1100) or secondary roads (S1200) in the MTDB. Secondary roads are main arteries, usually in
the U.S. highway, state highway, or county highway system. These roads have one or more lanes of
traffic in each direction, may or may not be divided, and usually have at-grade intersections with many
other roads and driveways. These roads often have both a local name and a route number.
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The all roads shapefile contains all linear street features with Street (“S”) type MTFCCs in the MTDB
(e.g., primary roads, secondary roads, local neighborhood roads, rural roads, city streets, vehicular trails
[4WD], ramps, service drives, walkways, stairways, alleys and private roads).
The Census Bureau works continuously to improve the accuracy of the features in the MTDB, including a
recent focus on highway review. However, some street features may have a misclassified MTFCC. There
can be gaps in features in the primary roads or the primary and secondary roads shapefiles, if a segment
of the feature was misclassified as a local neighborhood road, rural road, or city street (S1400) instead of
a primary road (S1100) or secondary road (S1200).
The all roads shapefile will contain multiple overlapping road segments where a segment is associated
with more than one road feature. For example, if a road segment is associated with US Route 36 and
State Highway 7 and 28th Street, the all roads shapefile will contain three spatially coincident segments,
each with a different name. The all lines shapefile contains the set of unique road segments for each
county, along with other linear features. Note that the linear feature address range identifier (LINEARID)
field can link the linear features back to the featnames table. From there the TLID can relate the feature
back to the all lines shapefile.
See Appendix L-3.1 Primary Roads National Record Layout.
See Appendix L-3.2 Primary and Secondary Roads State-based Record Layout.
See Appendix L-3.3 All Roads County-based Record Layout.
4.12.4 Address Ranges Linear address range features and attributes are available in the following layer:
Address Range Feature County-based Shapefile
• The address range feature county-based shapefile contains the geospatial edge geometry and
attributes of all unsuppressed address ranges for a county or county equivalent area. All the
TIGER/Line address range files contain potential address ranges, not individual addresses.
Potential ranges include the full range of possible structure numbers even though the actual
structures may not exist. The Census Bureau suppresses single-address address ranges in order
to maintain the confidentiality of the described addresses as specified by Title 13 of the U.S.
Code, and does not currently provide any address ranges for the Island areas.
The address range feature shapefile contains all the address range to street name relationships in the
address range feature name relationship file. The address range feature shapefile also contains all
possible relationships between the address range county-based relationship file (see Appendix R-1) and
the all lines shapefile. The address range feature shapefile will result in better geocoding match rates
compared with using the all lines shapefile. The all lines shapefile only contains the most inclusive
address range associated with each side of a street edge and the primary street name assigned to the
edge.
See Appendix L-4 for Address Range Feature County-based Record Layout.
4.12.5 Railroads Linear railroad features and attributes are available in the following layer:
The railroad shapefile includes spur lines and rail yards, mass transit rail lines (e.g., carlines, streetcar
track, monorail, or other mass transit rail), and special purpose rail lines (e.g., cog rail lines, incline rail
lines, and trams). The railroad shapefile contains all linear rail features with rail (“R”) type MTFCCs in the
MTDB. The Census Bureau provides these shapefiles at a national geographic extent and in a linear
elemental feature geometry.
See Appendix L-5 for Railroads National Record Layout.
4.13 Metropolitan and Micropolitan Statistical Areas and Related Statistical Areas Metropolitan and micropolitan statistical areas and related statistical area geography and attributes are
available in the following current shapefiles:
Combined New England City and Town Area (CNECTA) National
Combined Statistical Area (CSA) National
Metropolitan Division National
Core Based Statistical Areas (CBSA) National (Metropolitan and Micropolitan Statistical Areas)
New England City and Town Area (NECTA) National
New England City and Town Area (NECTA) Division National
Figure 22: Metropolitan and Micropolitan Statistical Areas
In March 2020, the U.S. Office of Management and Budget (OMB) announced updates to metropolitan
and micropolitan delineations, superseding the delineations published on July 15, 2015, and based on
official standards published in the Federal Register on June 28, 2010 (OMB 17-01). The interagency
Metropolitan Area Standards Review Committee developed these standards to provide a nationally
consistent set of geographic entities for the United States and Puerto Rico. The OMB has not defined
metropolitan or micropolitan geography in the Island areas.
A metropolitan or micropolitan statistical area contains a core area with a substantial population nucleus,
as well as adjacent communities having a high degree of economic and social integration with that core.
Core Based Statistical Area (CBSA) term became effective in 2000 and refers collectively to metropolitan
and micropolitan statistical areas.
Each metropolitan statistical area must have one urbanized area of 50,000 or more inhabitants. Each
micropolitan statistical area must have one urban cluster of 10,000 to 49,999 inhabitants. The
categorization of CBSAs as either metropolitan or micropolitan statistical areas is based on the population
in the most populous (or dominant) core, not the total CBSA population or the total population of all
(multiple) cores within the CBSA.
Counties or equivalent entities form the building blocks for metropolitan and micropolitan statistical areas.
Central counties are those counties or equivalent entities in which 50 percent of the population resides
within urban areas of 10,000 (or more) population, or that contain 5,000 people residing within a single
urban area of 10,000 (or more) population. Additional outlying counties that meet specified requirements
of commuting to or from the central counties may be included in the CBSA.
In New England (Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont), the
OMB has defined an alternative county subdivision (generally city and town) based definition of CBSAs
known as New England City and Town Areas (NECTAs). NECTAs have the same criteria as metropolitan
See Appendix H for records layouts on SLDL and SLDU.
4.20 Subbarrio (Subminor Civil Division) (Puerto Rico) Subbarrio (Subminor civil division - sub-MCD) geography and attributes for Puerto Rico are available in
4.22 Urban Areas Urban area geography and attributes are available in the following shapefile:
Urban Area National Shapefile (2010 Census)
For the 2010 Census, the Census Bureau classified all territory, population, and housing units located
within Urbanized Areas (UAs) and Urban Clusters (UCs) as urban. The Census Bureau delineates UA
and UC boundaries to represent densely developed territory, encompassing residential, commercial, and
other non-residential urban land uses. In general, this territory consists of areas of high population density
and urban land use resulting in a representation of the urban footprint. Rural areas consist of territory,
population, and housing units located outside of UAs and UCs.
For the 2010 Census, the urban and rural classification applied to the 50 States, the District of Columbia, Puerto Rico, and the Island Areas. Urbanized Areas (UAs) consists of densely developed territory that contains 50,000 (or more) people. The Census Bureau delineates UAs to provide a better separation of urban and rural territory, population, and housing surrounding large places. The Census Bureau first introduced the urbanized area concept for the 1950 Census. Urban Clusters (UCs) consists of densely developed territory that has 2,500 to 49,999 people. The
Census Bureau first introduced the UC concept for the 2000 Census to provide a more consistent and
accurate measure of urban population, housing, and territory throughout the United States, Puerto Rico,
and the Island Areas. The Census Bureau identifies all qualifying urban areas in Guam, the
Commonwealth of the Northern Mariana Islands, and the U.S. Virgin Islands as urban clusters based on
agreements with the local governments. Thus, in the Island Areas, urban clusters may exceed 50,000
people.
Urban Area Titles and Codes—The title of each UA and UC may consist of up to three incorporated place
or CDP names and will include the 2-letter U.S. Postal Service abbreviation for each state or statistically
equivalent entity into which the UA or UC extends. However, if the UA or UC does not contain an
incorporated place or CDP, the urban area title will include the single name of an MCD or populated place
recognized by GNIS.
Each UC and UA has a 5-character code, based on a national alphabetical sequence of all urban area
names. A separate flag is included in data tabulation files to differentiate between UAs and UCs. In
printed reports, this differentiation is included in the name.
Relationship to Other Geographic Entities
The Census Bureau delineates urban areas at the block level. Urban areas may cross the boundaries of
all other geographic areas for which the Census Bureau presents data, which means that all areas, other
than blocks, may include both urban and rural areas.